The area changes corresponding to the waterline shown in Figure 21 were 
determined for a length of shoreline extending 2,550 feet north of the north 
breakwater. These areas are summarized in Table 3. A correction is applied 
for the variation in lake level by the relationship 
Correction in 1,000 square feet = sp ~ take Tevet ot rference ~ 2,580 
which follows the assumption of an average beach slope of 1 on 45 for this area 
as determined from the 1945 surveys. 
Table 3. Summary of shoreline accretion rates north 
of Holland Harbor (1849-1945). 
Measured area from | Lake level Lake level Area Net area Rate 
breakwater to (N.Y. datum) difference | correction 
2,550 feet north 
(1,000 ft? (ft) (ft) (1,000 £t2) | (1,000 ft?) | (1,000 £t2/yr) 
The results of the computations (Table 3) indicate rates of accretion vary- 
ing from 3,400 to 51,900 cubic yards per year if the general rule of 1 square 
foot of beach area corresponds to 1 cubic yard of beach material is applied. 
These accretion rates should be interpreted according to the history of the 
construction. The first breakwaters were constructed in 1856-60 and trapped 
most, if not all, of the littoral drift. Since the accretion of 51,900 square 
feet per year during the period 1856-71 is an average, then the corresponding 
littoral drift rate must have exceeded 51,900 cubic yards per year (it must be 
assumed that by 1871 some of the littoral transport was passing around the break- 
water heads into the navigation channel). 
The accretion was slowed to 3,400 square feet per year from 1871 until the 
harbor breakwater extensions were started in 1906. Therefore, the littoral 
transport passing around the north breakwater must have been quite high from 
1871 to 1906; also, the building of new dunes by wind action probably occurred 
during this period. 
From 1906 to 1933 the accretion averaged 13,700 square feet per year; after 
1933 this rate dropped slightly to 13,400 square feet per year. However, some 
inland dune building could still be taking place. Measurements from the 1945 
survey show an accumulated volume of 137,400 cubic yards above elevation 585 
(1945 datum) on the north side of Holland Harbor. This volume would only 
account ror about 1,900 cubic yards per year from 1871 to 1945 but windblown 
sand losses farther inland would increase this. 
The detailed analysis of aerial photos taken from 1950 to 1973 indicates 
an average accretion rate of about 1.65 feet per year per foot of shoreline for 
the first 4,000 feet of shoreline north of the harbor, a total of 6,600 square 
feet per year. The accretion rate based on a comparison of the 1945 and 1973 
hydrographic surveys for profiles 1, 2, and 3 in Figure 10 was about 4,800 
52 
